Under the iTunes in the Cloud section, click Manage Devices. (If you haven't associated any devices with your Apple ID, you won't see the Manage Devices section.) Information about each associated device appears. Next to each device, you can see when it associated with your Apple ID.
The real reason why the burp smells so badly is hydrogen sulfide (H2S). If you eat foods that have sulfur proteins in them then you may find yourself burping the H2S, which will smell like rotten eggs. The sulfur reducing microbes in the intestine digest the proteins and release the gas.
Burping refers to releasing air and other gases from the stomach through mouth. Sulfur burps are a kind of burp which smells like rotten eggs or sulfur. This smell is because of the hydrogen sulfide gas which sulfur proteins contain.